DE1603874A1 - Torque control device for compressed air wrenches - Google Patents

Description

8000 MUNICH 2

VAL 33

TELEPHONE 0811/226894

TELEGRAM ADDRESS: THOPATENT

Munich August 26, 1969

Patent application

P 16 03 87 ^ .7

case POS-10775 MA / T 23 ^ 7

Kobe Steel, Ltd. and

The Nippon Airbrake Co., Ltd.
Kobe-shi, Japan

Torque control device for
Pneumatic wrench

The invention relates to a device for Control of the torque of pneumatic wrenches, • such as the so-called bump key, in which the circulating energy collected in a rotor with the help of a slide Ratschonmochanismus is converted into impact energy in order to a driven element such as a screw to apply a 'threatening torque'.

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(Art J Si \ Aba. 2 Mr. 1 Sentence 3 the Amendment Veas. V. 4.0.

BAD ORHä'MAL

When tightening an element such as a screw using a pneumatic wrench an extremely complicated handling is necessary up to now which includes adjusting the tightening force by using a torque lock whenever the Tightening force is limited so that it falls within a predetermined range. There are numerous ways to solve this problem Types of pneumatic wrenches have been proposed that pre-adjust the torque generated by them to one control a predetermined value and thereby limit the tightening force. However, as in most cases this conventional pneumatic Wrenches the control device is built in, they have! Necessary / large dimensions and considerable weight, Therefore, these wrenches have the disadvantages of being inconvenient in handling, complicated in construction and difficult to maintain and adjust, and furthermore only. for Screws with relatively small dimensions can be used. The same is more or less true of the pneumatic ones Wrench to which the control device is outside appropriate '. Wrenches of this type, in particular, are generally complex in construction and difficult to adjust of the torque o and nioht'simple in maintenance.

According to the invention, a torque control device ^ \\\ ·· * ο-sehün, which not only work on conventional pneumatic screw

• .10 9811/0159 bathroom original

keys can be attached, but also simply in the Maintenance and in adjustment is and the-a torque in stable way and control the working period of the concerned Shorten the wrench and prevent waste of air can. ·· ■.

The invention is explained in more detail below with reference to schematic drawings of several exemplary embodiments. Show it:

! Pig. 1 shows the working curve of a pneumatic wrench and

Pig. 2 and 3 circuit diagrams show different ones Embodiments of the torque control device according to the invention.

In the pig. 1 shows the general relationship between the torque T generated by a pneumatic wrench, the working period S and the pressure P applied to the wrench. How to get out. As can be seen from this diagram, a desired torque T ₁ can be obtained either by limiting the operating period of the pneumatic wrench to S _{1 at a pressure of P 1} or, alternatively, by lowering the pressure to P ₉ and the wrench for one period S is _{operating 2} or more The first method is advantageous * because it shortens the working period of the wrench, but has the

! Disadvantage that the torque obtained is unstable, while the

10 9811/0159 'ORIGINAL BATHROOM

the latter method has the advantage that it is possible to use the result for a sufficiently long period relatively to obtain stable torque, but on the other hand, there is the compartment part that compressed air is wasted oaer the desired torque is not achieved if the working period is not long enough. To avoid these disadvantages, both methods should therefore be appropriately coded will. It could be stable without wasting air and time. Torque T .. were thereby obtained -.-..-.- ' the feed pressure set to Pp and the working period au. Sp is limited.

Based on this concept, the invention has a pressure reducing valve for regulating the pressure of an associated one pneumatic wrench supplied air and a shuttle valve for blocking a channel for this air, in order to allow the operation of the wrench after expiration a predetermined time to stop, wherein the shuttle valve is automatically operated with the aid of a timer, whereby the pressure of the air supplied to the wrench and. the working period of the key can be brought to the desired values in order to achieve this. to control the torque reached.

Fig. 2 shows an embodiment of the inventive geniäSen Device with an electrical timing element. In this execution form the pneumatic circuit includes a pressure reducing valve 1 for regulating the pressure from under pressure

10 9 8 11/0159 BATH ORIGINAL

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a compressed air source SUP to an associated pneumatic wrench 2 and an electrically operated changeover switch 3, which is connected between the pressure reducing valve 1 and the wrench 2, in order to switch the Sördervreg from the former to the latter. The inlet side and the outlet side of the shuttle valve are connected to each other through a throttle portion 4 _V ,, wherein a pressure difference is used between the two sides of the throttle portion 4 -one for actuating switch actuator 5. on the other hand, the electrical 'has circuit includes a to-use by the switch actuator 5 blocking Schälter 6 »one in a A predetermined time period to be opened time switch 7 and a magnet SOL for actuating the aforementioned shuttle valve 3. If the wrench 2 is not in operation, the main compressed air path leading from the pressure reducing valve 1 to the wrench 2 is closed through the shuttle valve 3 ^, as e is shown in the figure, so that the pressures on the front and back of the throttle section 4 are balanced .. As a result, the switch actuator 5 is out of operation and keeps the switch 6 in the open position * V / ird for the use of the pneumatic wrench a valve is opened at this, the compressed air located on the back of the throttle section 4 is first consumed and. In this way, a pressure difference is formed between both sides ae.3 I / ruijuelabK & hnitts. By diGvTe pressure difference, the switch actuation device 5 is actuated and α or switch 6 ^ e sch Io a ο en-, although the screw axis 2 in ä; 'f ;;; ern state not yet put into operation int, Be in V, a). ~. ie con

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of the switch 6, the solenoid SOl is activated, uni the shuttle valve 3 in the open position and thereby the wrench 2 in motion. The switch 6 is continuously held in the closed position even when the switch actuator 5 after removing the pressure difference between the two sides of the section 4 in its original position is kehct. After a predetermined period of time, the time switch 7- is actuated to activate the electromagnet SOI to relax, whereupon the shuttle valve is closed and the operation of the wrench 2 is stopped. While closing of the shuttle valve'3 is again between both sides of the throttle section 4 a pressure difference built up, so that the switch actuator 5 is actuated again and the lock switch 6 leads to the open position. When the valve in the wrench 2 is closed, the pressure difference is canceled; so that the switch actuator 5 returns to its original position. In this way, the entire facility is completely decommissioned as it was before commissioning.

BATH ORIGINAL

10981 1/0159

'■■■ "" 1803874

As has emerged from the above, the torque generated by the pneumatic wrench is automatically controlled by regulating the air pressure supplied to the veraubenschlüssei and the builder of its supply so that the operator can only operate the valve of the wrench and as long as: needs to hold until the operation is automatically stopped. There is no need to adjust the tightening force using a torque wrench or the like, as was necessary with the * conventional wrenches. With the device according to the invention, it is therefore possible to tighten with ease, which has hitherto required the experience of the operator furthermore, an even tightening force is ensured in the parts to be tightened. Accordingly, it is possible to avoid excessive or insufficient tightening forces with wasteful consumption of compressed air due to unnecessarily long operation of the wrench, which is disadvantageous even for people with experience in tightening using an impact wrench A further advantage of the device according to the invention is that it can be easily connected to pneumatic wrenches of conventional design and without difficulty keit geha ^; ndhäbt-can.

1098 1170159

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Claims (1)

Paterite claim Torque control device for pneumatic wrenches, characterized by a pressure reducing valve3. ^r l ^s to regulate the compressed air supply to the wrench. Main air line between the pressure reducing valve U ₁ - 'Icr wrench j through a solenoid-operated shuttle valve (3 / for opening and closing the line) arranged in the main air line, through a secondary line with a throttle valve (4) arranged in series, with the upstream end of the secondary line between the pressure reducing valve and the shuttle valve opens into the main air line and the downstream end of the secondary line between the shuttle valve and the wrench opens into the main air line through a pneumatically operated switch actuator which is actuated by the pressure difference in the secondary line at the throttle valve an electrical circuit for energizing the solenoid of the shuttle valve, by a timer (7) which is provided in the circuit and opens the circuit in a predetermined time after using the wrench by opening an operating valve .des wrench , through a blocking. 109811/0159 ■ jua Urnt-nu. ^, ■ ι ■ ·. ι '^; . · Ι au. 2 λ ', ·, ι su- · ju *. Αΐι ^ & ι,. ,, ια ^ ■ · - ν. <ι. a. To the circuit only to Schliemann ■ S) Qn ₁ when the switch actuator to open by the Bcdienungsventils is operated at the wrench, and to the circuit only to open switch in the circuit, which is actuated by the switch actuating member (5) when the switch ^{actuator 4} member is operated and the timer opens the circuit for closing the shuttle valve in the main air line. 10901 i / 0159 Blank page